This invention relates to optical fibre connectors and relates more specifically to such connectors of the so-called expanded beam type.
Expanded beam optical fibre connectors may comprise an least one convex (e.g. sphere) lens which is maintained in predetermined spaced alignment with the polished end face of an optical fibre which may be retained within the central aperture of a support ferrule (e.g. ceramic).
For the purpose of ensuring that the end face of the optical fibre is in precise active and mechanical spaced alignment with a sphere lens, the lens and the optical fibre terminating end of the ferrule may be seated against the respective surfaces of axially-spaced oppositely facing precision-machined conically-shaped cavities defined by the profile of a main bore of a lens/ferrule support structure which provides a relatively small bore extending between the respective cavities affording active alignment of the optical fibre end face relative to the sphere lens.
To avoid the need for providing such conical cavities which can only be precision machined from opposite ends of the main bore in the support structure for accommodating the lens/ferrule assembly, the sphere lens and the optical fibre terminating ferrule may be positioned in predetermined spaced relationship with each other by the interposition of a spacer plate between the lens and the fibre terminating end of the ferrule.
However, in a known construction of expanded beam connector a spacer plate is provided having a central aperture with a flared end portion on which the sphere lens is seated to provide the requisite alignment and spacing between the sphere lens and the end face of the ferrule-terminated optical fibre. The sphere lens, spacer and ferrule are held captive within a hollow cylindrical housing providing the aforesaid main bore and co-operating therewith to provide a discrete optical contact assembly for insertion into an aperture in a connector body. A plurality of such discrete contact assemblies may be positioned in respective apertures of the connector body in the case of a multi-way expanded beam optical connector.
The sphere lens, spacer plate and optical fibre-terminating ferrule of this known construction of connector are held captive in the housing by means of a tubular member which is a press fit in the housing and provides a fixed abutment for the end of the optical fibre terminating ferrule remote from the spacer-plate and sphere lens while radially inwardly deformed retention fingers formed integrally with the cylindrical housing bear directly against the sphere lens to retain the lens at the front end of the assembly.
Although this known construction of connector avoids the previously mentioned need for precision machining of the main bore profile from opposite ends thereof to provide conical seatings for the sphere lens and optical fibre terminating ferrule it does not provide for the ready removal of the sphere lens, spacer plate and optical fibre terminating ferrule from the main bore, such as to facilitate cleaning of the assembly component parts.
The present invention is directed therefore to an improved construction of optical fibre connector of the expanded beam type which facilitates the easy removal of the lens, spacer plate and ferrule components from the main bore of an assembly and which may avoid the use of a separate hollow cylindrical housing to provide the main bore for the lens, spacer and ferrule assembly components.